Download Bio 135 Ch. 11 Rev Guide

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__ Bio 135 Ch. 11 Review Guide 1. Why did Gregor Mendel use pea plants to study? 2. What do we call offspring that result from crosses between parents with different traits. 3. What did Gregor Mendel conclude about traits? 4. When Gregor Mendel crosses a tall plant with a short plant, what did the F1 plants inherit? 5. What does the principle of dominance state? 6. When Gregor Mendel crosses true-­‐breeding tall plants with true-­‐breeding short plants, why were all of the plants tall? 7. A tall plant is crossed with a short plant. If the tall F1 pea plants are allowed to self-­‐pollinate, the offspring will be….. 8. How do geneticists use the principles of probability? 9. In the P generation, a tall plant is crossed with a short plant. What is the probability that the F2 plants will be tall? 10. What do we call organisms that have two identical alleles for a particular trait? 11. T represents dominant tall. t represents recessive short. Make a Punnett square crossing parents with the genotypes TT and Tt. Describe the genotypes and phenotypes of the offspring. What are the probabilities of each? 12. List three things a Punnett square can show. 13. Make a Punnett square showing Gregor Mendel’s cross between true-­‐breeding tall plants and true-­‐breeding short plants. List the phenotypes and genotypes of the offspring and the probabilities of each. 14. What principle states that during gamete formation genes for different traits separate without influencing each other’s inheritance? 15. How many different allele combinations would be found in the gametes produced by a pea plant whose genotype was RrYY? (HINT: list the possible allele combinations first, just as if you were setting up a Punnett square for a dihybrid cross) 16. Assume that R is round, r is wrinkled, Y is yellow, and y is green. If a pea plant that is heterozygous for round, yellow peas (RrYy) is crossed with a pea plant that is homozygous for round peas but heterozygous for yellow peas (RRYy), how many different phenotypes are their offspring expected to show? 17. Situations in which one allele for a gene is not completely dominant over another allele for that gene are called. 18. A cross of a black chicken (BB) and a white chicken (WW) produces all speckled offspring (BBWW). What do we call this type of inheritance? 19. Variation in human skin color is an example of 20. To what organisms do Gregor Mendel’s principle of genetics apply? 21. A male and female bison that are both heterozygous for normal skin pigmentation (Aa) produce an albino offspring (aa). Which of Mendel’s principles explain(s) why the offspring is albino? (choices: dominance, independent assortment, segregation – may be more than one) 22. If an organism’s diploid number is 12, what is its haploid number? 23. Gametes have (choose one) homologous chromosomes twice the number of chromosomes found in body cells two sets of chromosomes one allele for each gene 24. What process produces gametes? 25. Know what crossing over is, what it looks like, and how it changes the chromosomes. (see text p. 277, fig 11-­‐16) 26. What happens between meiosis I and meiosis II that reduces the number of chromosomes? 27./28. Unlike mitosis, meiosis results in the formation of ….(number of cells, haploid/diploid, genetic similarity to parent cell) 29. Describe linked genes 30. The farther apart two genes are located on a chromosome, the less likely they are to be inherited together more likely they are to be linked less likely they are to assort independently less likely they are to be separated by a crossover during meiosis Short answer: Given a dihybrid cross (BbRr x BbRr): 31. Be able to fill in the Punnett square, and describe the phenotypes for each square 32. Identify all of the different genotypes 33./34. What fraction of the offspring would show each of the different phenotypes 35. What do the letters represent in a genetic cross? 36. Understand the concept of incomplete dominance. (p. 272) 37. How do you know if an individual is showing incomplete dominance? 38./39. Predict the offspring of a particular cross, given the parents genotypes and that this characteristic shows incomplete dominance.